Bluetooth: use hdev lock for accept_list and reject_list in conn req

All accesses (both reads and modifications) to
hdev->{accept,reject}_list are protected by hdev lock,
except the ones in hci_conn_request_evt. This can cause a race
condition in the form of a list corruption.
The solution is to protect these lists in hci_conn_request_evt as well.

I was unable to find the exact commit that introduced the issue for the
reject list, I was only able to find it for the accept list.

Fixes: a55bd29 ("Bluetooth: Add white list lookup for incoming connection requests")
Signed-off-by: Niels Dossche <[email protected]>
Signed-off-by: Marcel Holtmann <[email protected]>

Author: nielsdos

net/bluetooth/hci_event.c

@@ -3225,10 +3225,12 @@ static void hci_conn_request_evt(struct hci_dev *hdev, void *data,
 		return;
 	}
 
+	hci_dev_lock(hdev);
+
 	if (hci_bdaddr_list_lookup(&hdev->reject_list, &ev->bdaddr,
 				   BDADDR_BREDR)) {
 		hci_reject_conn(hdev, &ev->bdaddr);
-		return;
+		goto unlock;
 	}
 
 	/* Require HCI_CONNECTABLE or an accept list entry to accept the
@@ -3240,13 +3242,11 @@ static void hci_conn_request_evt(struct hci_dev *hdev, void *data,
 	    !hci_bdaddr_list_lookup_with_flags(&hdev->accept_list, &ev->bdaddr,
 					       BDADDR_BREDR)) {
 		hci_reject_conn(hdev, &ev->bdaddr);
-		return;
+		goto unlock;
 	}
 
 	/* Connection accepted */
 
-	hci_dev_lock(hdev);
-
 	ie = hci_inquiry_cache_lookup(hdev, &ev->bdaddr);
 	if (ie)
 		memcpy(ie->data.dev_class, ev->dev_class, 3);
@@ -3258,8 +3258,7 @@ static void hci_conn_request_evt(struct hci_dev *hdev, void *data,
 				    HCI_ROLE_SLAVE);
 		if (!conn) {
 			bt_dev_err(hdev, "no memory for new connection");
-			hci_dev_unlock(hdev);
-			return;
+			goto unlock;
 		}
 	}
 
@@ -3299,6 +3298,10 @@ static void hci_conn_request_evt(struct hci_dev *hdev, void *data,
 		conn->state = BT_CONNECT2;
 		hci_connect_cfm(conn, 0);
 	}
+
+	return;
+unlock:
+	hci_dev_unlock(hdev);
 }
 
 static u8 hci_to_mgmt_reason(u8 err)